Backup Crew

Flight

This was the sixth of nine
planned missions to
Mir and the third one involving an exchange of
U.S. astronauts. Astronaut Jerry
Linenger, who was on
Mir since January 15, 1997, was replaced by astronaut
Michael Foale. He spent more than four months on
Mir. He returned to Earth on Space Shuttle Mission
STS-86, launched in September
1997.Atlantis again carried the SPACEHAB module in the payload bay of the
orbiter. The double module configuration housed experiments to be performed by
Atlantis' crew along with logistics equipment to be transferred to
Mir.The prior Shuttle-Mir missions were STS-71, STS-74,
STS-76,
STS-79 and
STS-81.

About two hours before the scheduled docking time on Flight Day
Three of the mission, Atlantis reached a point about eight nautical miles (14.8
km) behind the
Mir Space Station and conducted a Terminal Phase
Initiation (TI) burn, beginning the final phase of the rendezvous. Atlantis
closed the final eight nautical miles (14.8 km) to
Mir during the next orbit. As Atlantis approaches, the
shuttle's rendezvous radar system began tracking
Mir and providing range and closing rate information
to Atlantis. Atlantis' crew also began air-to-air communications with the
Mir crew using a VHF radio.As Atlantis reached
close proximity to
Mir, the Trajectory Control Sensor, a laser ranging
device mounted in the payload bay, supplemented the shuttle's onboard
navigation information by supplying additional data on the range and closing
rate. As Atlantis closed in on the
Mir, the shuttle had the opportunity for four small
successive engine firings to fine-tune its approach using its onboard
navigation information. Identical to prior
Mir dockings, Atlantis aimed for a point directly
below
Mir, along the Earth radius vector (R-Bar), an
imaginary line drawn between the
Mir center of gravity and the center of Earth.
Approaching along the R-Bar, from directly underneath the
Mir, allows natural forces to assist in braking
Atlantis' approach. During this approach, the crew began using a handheld laser
ranging device to supplement distance and closing rate measurements made by
other shuttle navigational equipment.The manual phase of the rendezvous
began just as Atlantis reached a point about a half-mile (900 meters) below
Mir. Commander Charles
Precourt flew the shuttle using the aft flight deck controls
as Atlantis began moving up toward
Mir. Because of the approach from underneath
Mir, Charles
Precourt had to perform very few braking firings. However, if
such firings were required, the Shuttle's jets were used in a mode called
"Low-Z", a technique that uses slightly offset jets on Atlantis' nose and tail
to slow the spacecraft rather than firing jets pointed directly at
Mir. This technique avoids contamination of the space
station and its solar arrays by exhaust from the shuttle steering
jets.Using the centerline camera fixed in the center of Atlantis' docking
mechanism, Charles
Precourt centered Atlantis' docking mechanism with the
Docking
Module mechanism on
Mir, continually refining this alignment as he
approached within 300 feet (91.4 meters) of the station.At a distance of
about 30 feet (9.14 meters) from docking, Charles
Precourt stopped Atlantis and held stationkeep momentarily to
adjust the docking mechanism alignment, if necessary. At that time, a final go
or no-go decision to proceed with the docking was made by flight control teams
in both Houston and Moscow.When Atlantis proceeded with docking, the
shuttle crew used ship-to-ship communications with
Mir to inform the
Mir crew of the Shuttle's status and to keep them
informed of major events, including confirmation of contact, capture and the
conclusion of damping. Damping, the halt of any relative motion between the two
spacecraft after docking, was performed by shock absorber-type springs within
the docking device. Mission Specialist Jean-François
Clervoy had to oversee the operation of the Orbiter Docking
System from onboard Atlantis.STS-84 docking with
Mir occurred on May 17, 1997 at 02:33
UTC above the Adriatic Sea. Hatches between two
spacecraft opened at 08:25
UTC May 17, 1997. Greetings exchanged between
STS-84 crew and
Mir-23Commander Vasili
Tsibliyev,
Flight Engineer Aleksandr
Lazutkin and Jerry
Linenger, followed by a safety briefing. Jerry
Linenger and Michael
Foale officially traded places at 14:15
UTC.

STS-84 involved the transfer of 3,318 kilograms (7,310
lb) of water and logistics to and from the
Mir. During the docked phase, 465 kilograms (1,030 lb)
of water, 383.2 kilograms (845 lb) of U.S. science equipment, 1,168.6 kilograms
(2,576 lb) of Russian logistics along with 178.1 kilograms (393 lb) of
miscellaneous material were transferred to
Mir. Returning to Earth aboard Atlantis were 407.1
kilograms (898 lb) of U.S. science material, 531.2 kilograms (1,171 lb) of
Russian logistics, 14 kilograms (31 lb) of
ESA
material and 170.7 kilograms (376 lb) of miscellaneous
material.

Transfer of items to and from
Mir proceeded smoothly and was completed ahead of
schedule. One of first items transferred to station was an Elektron
oxygen-generating unit. Altogether about 249 items were moved between the two
spacecraft, and about 450 kilograms (990 lb) of water moved to
Mir, for a total of about 3,400 kilograms (7,500 lb)
of water, experiment samples, supplies and hardware.

The
Mir-23 mission began
when the cosmonaut crew launched on February 10, 1997, in
Soyuz TM-25 and docked with the
Mir two days later. Jerry
Linenger joined the
Mir-22 crew with the
January 14, 1997 docking of Atlantis during Mission
STS-81. The return of Atlantis on
STS-84 concluded some experiments, continued others
and commenced still others. Data gained from the mission will supply insight
for the planning and development of the International Space Station,
Earth-based sciences of human and biological processes, and the advancement of
commercial technology.

The research program conducted by Michael
Foale featured 35 investigations total (33 on
Mir, two on
STS-84, and another preflight/postflight) in six
disciplines: advanced technology, Earth observations and remote sensing,
fundamental biology, human life sciences, space station risk mitigation, and
microgravity sciences. Twenty-eight of these were conducted during previous
missions and were to be continued, repeated or completed during Michael
Foales stay. Seven new experiments were planned in biological
and crystal growth studies and materials processing.

Earth sciences
research in ocean biochemistry, land surface hydrology, meteorology, and
atmospheric physics and chemistry also were performed. Observation and
documentation of transient natural and human-induced changes were accomplished
with the use of passive microwave radiometers, a visible region spectrometer, a
side-looking radar, and hand-held photography. Earth orbit allowed for
documentation of atmospheric conditions, ecological and unpredictable events,
and seasonal changes over long time periods.Fundamental biology research
continued developmental investigations that study the effects of the space
environment on the biological systems of plants. Prolonged exposure to
microgravity provides an ideal opportunity to determine the role gravity has on
cell regulation and how this affects development and growth. Investigations
under this discipline will also characterize the internal radiation environment
of the
Mir space station.

Human life sciences research
consisted of investigations that focus on the crewmember's adaptation to
weightlessness in terms of skeletal muscle and bone changes, psychological
interactions, immune system function, and metabolism. In addition,
environmental factors such as water quality, air quality, surface assessment
for microbes, and crew microbiology were assessed. These ambitious
investigations continued the characterization of the integrated human responses
to a prolonged presence in space.

Space science research continued with
the externally mounted
Mir Sample Return Experiment (MSRE) and Particle
Impact Experiment (PIE) payloads. These experiments continued to collect
interstellar and interplanetary space particles to further our understanding of
the origin and evolution of planetary systems and life on
Earth.

Environmental Radiation Measurements: Exposure of crew,
equipment, and experiments to the ambient space radiation environment in low
Earth orbit poses one of the most significant problems to long term space
habitation. As part of the collaborative
NASA/Mir Science program, a series of measurements were
compiled of the ionizing radiation levels aboard
Mir. During the mission, radiation was measured in six
separate locations throughout the
Mir using a variety of passive radiation detectors.
This experiment continued on later missions, where measurements will be used to
map the ionizing radiation environment of
Mir. These measurements will yield detailed
information on spacecraft shielding in the 51.6-degree-orbit of the
Mir. Comparisons were made with predictions from space
environment and radiation transport models.

Greenhouse-Integrated
Plant Experiments: The microgravity environment of the
Mir space station provided researchers an outstanding
opportunity to study the effects of gravity on plants, specifically dwarf
wheat. The greenhouse experiment determined the effects of space flight on
plant growth, reproduction, metabolism, and production. By studying the
chemical, biochemical, and structural changes in plant tissues, researchers
hoped to understand how processes such as photosynthesis, respiration,
transpiration, stomatal conductance, and water use are affected by the space
station environment. This study was an important area of research, due to the
fact that plants could eventually be a major contributor to life support
systems for space flight. Plants produce oxygen and food, while eliminating
carbon dioxide and excess humidity from the environment. These functions are
vital for sustaining life in a closed environment such as the
Mir or the International Space
Station.

Human Life Sciences: The task of safely keeping men and
women in space for long durations, whether they are doing research in Earth
orbit or exploring other planets in our solar system, requires continued
improvement in our understanding of the effects of space flight factors on the
ways humans live and work. The Human Life Sciences (HLS) project had a set of
investigations planned for the
Mir-24/NASA 5 mission to determine how the body adapts to
weightlessness and other space flight factors, including the psychological and
microbiological aspects of a confined environment and how they readapt to
Earth's gravitational forces. The results of these investigations will guide
the development of ways to minimize any negative effects so that crewmembers
can remain healthy and efficient during long flights, as well as after their
return to Earth.

Other activities conducted during the
mission included investigations using the Biorack facility, located in the
SPACEHAB Double Module in Atlantiss payload bay, a photo survey of
Mir during docked operations, environmental air
samplings and radiation monitoring.

Once Atlantis was ready to undock
from
Mir on May 21, 1997, the initial separation was
performed by springs that gently pushed the shuttle away from the
docking
module. Both the
Mir and Atlantis were in a mode called "free drift"
during the undocking, a mode that has the steering jets of each spacecraft shut
off to avoid any inadvertent firings.Once the docking mechanisms springs
have pushed Atlantis away to a distance of about two feet (61 centimeters) from
Mir, where the docking devices were clear of one
another, Atlantis steering jets were turned back on and fired in the Low-Z mode
to begin slowly moving away from
Mir.For the
STS-84 mission, Atlantis continued away from
Mir until it reached a distance of 3,000 feet (914
meters) below the
Mir in order to test a European laser docking sensor.
Unlike previous Shuttle-Mir flights, there was no fly-around of the station
for photo documentation. When Atlantis reached the 3,000 foot (914 meters)
distance, instead of firing jet thrusters to perform a separation maneuver, the
Shuttle depended on the natural forces of one spacecraft being in a lower orbit
than another which will cause the Shuttle to move ahead of the
Mir.New
ESA-developed technology was tested during the
Shuttle's approach and departure from
Mir. A
GPS receiver and an optical rendezvous sensor on the
Shuttle, together with equipment already installed on
Mir, were operated for the first time in space in an
enactment of how
ESAs
unmanned Automated Transfer Vehicle (ATV) will approach and depart the International Space
Station when it delivers supplies to it early in the next century.During
the long-range approach to
Mir (starting 3 hours before docking),
ESAs
European Proximity Operations Sensor
GPS receivers on Atlantis and
Mir received data from Navstar Global Positioning
Satellites on the position of the other craft. The accuracy of that relative
navigational data was later compared with true data from the Shuttles
rendezvous radar.When the Shuttle was at 170 feet (51.8 meters) from
Mir, the short-range experiment began. Navigation was
handed over to the optical rendezvous sensor. Data again were later be compared
to true figures, this time supplied by the
NASA Trajectory Control System (TCS), a laser ranging
device in the payload bay.

Note

Michael
Foale landed on October 06, 1997 at 21:55:08.547
UTC with STS-86.